Aminopropanol substituted indole compounds and compositions for the treatment of cardiac and circulatory diseases

ABSTRACT

New aminopropanol compounds of the formula ##STR1## wherein R is lower alkyl, cycloalkyl or alkylthioalkyl, 
     R 1  is hydrogen or lower alkyl, hydroxyalkyl, pivaloyloxyalkyl, alkoxyalkyl, alkoxycarbonyl, carboxyl or --CONR 3  R 4 , in which R 3  and R 4  which can be the same or different, represent hydrogen or lower alkyl, and 
     R 2  is lower alkyl, hydroxyalkyl, alkoxyalkyl or pivaloyloxyalkyl or, when R is alkylthioalkyl or R 1  is pivaloyloxyalkyl, R 2  can also be hydrogen and the pharmacologically acceptable salts thereof; are outstandingly effective in the treatment or prophylaxis of cardiac and circulatory diseases.

This is a continuation-in-part of application Ser. No. 805,558, filed June 10, 1977, now U.S. Pat. No. 4,152,446, which was a division of application Ser. No. 626,512, filed Oct. 28, 1975, now U.S. Pat. No. 4,076,829.

The present invention is concerned with new aminopropanol compounds, with therapeutic compositions containing them, and with methods for the treatment of cardiac and circulatory diseases using such compounds.

The new aminopropanol derivatives according to the present invention are compounds of the formula ##STR2## wherein R is lower alkyl, cycloalkyl or alkylthioalkyl,

R₁ is hydrogen or lower alkyl, hydroxyalkyl, pivaloyloxyalkyl, alkoxyalkyl, alkoxycarbonyl, carboxyl or --CONR₃ R₄, in which R₃ and R₄ which can be the same or different, represent hydrogen or lower alkyl, and

R₂ is lower alkyl, hydroxyalkyl, alkoxyalkyl or pivaloyloxyalkyl or, when R is alkylthioalkyl or R₁ is pivaloyloxyalkyl, R₂ can also be hydrogen and the pharmacologically acceptable salts thereof.

The alkyl radicals in the definitions of the substituents R, R₁, R₂, R₃, and R₄ can contain up to 6 and preferably up to 5 carbon atoms and can be straight or branched chained, the alkyl radicals in the definitions of the substituents R preferably being branched chained. The cycloalkyl radical R can contain 3 to 6 and preferably 3 or 4 carbon atoms.

The new compounds according to the present invention, as well as the pharmacologically compatible salts thereof, bring about an inhibition of the adrenogenic β-receptors and can, therefore, be used for the treatment or prophylaxis of cardiac and circulatory diseases.

The new compounds (I) according to the present invention can be prepared, for example, by one of the following methods:

(a) reaction of a compound of the general formula: ##STR3## with a compound of the general formula:

    Z--R'                                                      (III),

in which

R₁ and R₂ have the same meanings as above,

R' is a mercaptoalkyl radical or has the same meaning as R, one of the symbols

Y and Z stands for an amino group and the other for a reactive residue and

X is the group ═C═O or ═H--A whereby

A is a hydroxyl group or, together with Y, can also signify an oxygen atom; or

(b) reaction of a compound of the general formula: ##STR4## wherein R₁ and R₂ have the same meanings as above, with a compound of the general formula:

    Y'--CH.sub.2 --X--CH.sub.2 --NHR'                          (V),

wherein R' and X have the same meanings as above and Y' is a reactive residue; or

(c) for the case in which R is an alkylthioalkyl radical, reaction of a compound of the general formula: ##STR5## wherein R₁ and R₂ have the same meanings as above, B is a lower alkylene radical and X' signifies the group ═C═O or ═CHOH, with a compound of the general formula:

    HS--R.sub.5                                                (VII),

wherein R₅ is a hydrogen atom or a lower alkyl radical; or

(d) for the case in which R₁ and/or R₂ represents a pivaloyloxyalkyl radical, reaction of a compound of the general formula: ##STR6## wherein R' and X' have the same meanings as above and R'₁ and/or R'₂ represent a hydroxyalkyl group, whereby one of these symbols R'₁ or R'₂ can also have the same meaning as R₁ or R₂, with pivalic acid or with a reactive derivative thereof, whereafter, when R' is a mercaptoalkyl radical or R₅ is a hydrogen atom, alkylation is subsequently carried out on the sulfur atom and when X or X' is a ═C═O group, reduction is subsequently carried out and, if desired, in the compound thus obtained of general formula (I), one of the particular substituents R₁ is converted into a different substituent R₁ by saponification, esterification, transesterification, acylation or alkylation.

The compounds of general formula (I) obtained according to processes (a), (b), (c) or (d) can, if desired, be subsequently converted into their pharmacologically compatible salts.

The alkyl radicals in the definitions of the substituents R₅ and B can contain up to 6 and preferably up to 5 carbon atoms and can be straight or branched chained, preferably being branched chained. The cycloalkyl radical R₅ can contain 3 to 6 and preferably 3 or 4 carbon atoms.

The active residues Y, Z and Y' in compounds of general formulae (II), (III), and (V) are, in particular, acid residues, for example residues or hydrohalic or sulfonic acids.

Compounds of general formula (II) are described, for example, in Helv. Chim. Acta, 54 2418/1971 and amines of general formula (III) are described in German Pat. No. 2,045,905. Compounds of general formula (VI) can be obtained, for example, by the reaction of compounds of general formula (II) with compounds of the general formula HN B, wherein B has the same meaning as above.

The processes according to the present invention are preferably carried out in an organic solvent which is inert under the reaction conditions, for example, toluene, dioxan, ethylene glycol dimethyl ether, ethanol, n-butanol or dimethylformamide, optionally in the presence of an acid-binding agent. However, the reaction can also be accomplished, after mixing the reaction components, by leaving the reaction mixture to stand at ambient temperature or by heating.

The reaction of compounds of general formula (IV) with compounds of general formula (V) according to process (b) is preferably carried out with the exclusion of oxygen, in the presence of an acid acceptor. However, an alkali metal salt of the hydroxy compound of general formula (IV) can also be used.

The introduction of the pivaloyl radical into the hydroxyalkyl radical of compounds of general formula (VIII) according to process (d) takes place under the usual conditions of acylation, for example, by the reaction of compounds of general formula (VIII) with pivaloyl chloride, with cooling, in the presence of a base, such as pyridine.

The S-alkylation for the case is which R' in general formulae (III), (V) and (VIII) signifies a mercaptoalkyl radical or R₅ in general formula (VII) signifies a hydrogen atom, is also preferably carried out in a solvent of the above-mentioned type, with the exclusion of oxygen, using a conventional S-alkylation agent.

The reduction of the group ═C--O possibly to be carried out can be achieved by means of sodium borohydride or by catalytic hydrogenation in the presence of a noble metal catalyst.

The subsequent conversion of a radical R₁ into a different radical R₁ which it may be desired to carry out, can take place in conventional manner by saponification, esterification, transesterification, acylation or alkylation. For example, a compound of general formula (I), in which R₁ is an alkoxycarbonyl radical, can be subsequently saponified to give the corresponding carboxylic acid of general formula (I), in which R₁ is a carboxyl radical; this can be carried out in the uaual way, preferably in dilute aqueous alkali metal hydroxide solution.

For the conversion of compounds of general formula (I) into their pharmacologically compatible salts, these are reacted, preferably in an organic solvent, with an equivalent amount of an inorganic or organic acid, for example, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, acetic acid, citric acid, maleic acid or benzoic acid.

For the preparation of pharmaceutical compositions, the compounds of general formula (I) are mixed in known manner with appropriate pharmaceutical carrier substances, and with aroma, flavoring and coloring materials and formed, for example, into tablets or dragees or, with the addition of appropriate adjuvants, are suspended or dissolved in water or an oil, for example in olive oil.

The new compounds of general formula (I) according to the present invention and the salts thereof can be administered enterally or parenterally in liquid or solid form. As injection medium, water is preferably used which contains the additives usual for injection solutions, such as stabilizing agents, solubilizing agents or buffers. Additives of this type include, for example, tartrate and citrate buffers, ethanol, complex-forming agents (such as ethylenediamine-tetraacetic acid and the non-toxic salts thereof) and high molecular weight polymers (such as liquid polyethylene oxide) for viscosity regulation. Solid carrier materials include, for example, starch, lactose, mannitol, methyl cellulose, talc, highly dispersed silicic acids, high molecular weight fatty acids (such as stearic acid), gelatine, agar-agar, calcium phosphate, magnesium stearate, animal and vegatible fats and solid high molecular weight polymers (such as polyethylene glycols); compositions suitable for oral administration can, if desired, contain flavoring and sweetening materials.

Apart from the compounds mentioned in the following specific Examples, preferred compounds according to the present invention include the following:

4-[2-hydroxy-3-(1-propylthio-2-methylisopropylamino)-propoxy]-indole;

4-[2-hydroxy-3-(1-methylthiolisopropylamino)-propoxy]-indole;

4-[2-hydroxy-3-(2-methylthio-2-methylpropylamino)-propoxy]-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-methyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-hydroxymethyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-ethoxycarbonyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-carbamoyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-dimethylaminocarbonyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-carboxy-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-2-methoxymethyl-indole;

4-(2-hydroxy-3-sec.-butylaminopropoxy)-2-pivaloyloxymethyl-indole;

4-(2-hydroxy-3-cyclobutylaminopropoxy)-2-pivaloyloxymethyl-indole;

4-(2-hydroxy-3-tert.-pentylaminopropoxy)-2-pivaloyloxymethyl-indole;

4-(2-hydroxy-3-sec.-butylaminopropoxy)-6-hydroxymethyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-6-hydroxymethyl-indole;

4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-6-hydroxymethyl-indole;

4-[2-hydroxy-3-(1-ethylthio-2-methyl-isopropylamino)-propoxy]-6-hydroxymethyl-indole;

4-[2-hydroxy-3-(1-isopropylthio-2-methyl-isopropylamino)-propoxy]-6-hydroxymethyl-indole;

4-(2-hydroxy-3-sec.-butylaminopropoxy)-6-methyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-6-methyl-indole;

4-[2-hydroxy-3-(1-ethylthio-2-methyl-isopropylamino)-propoxy]-6-methyl-indole;

4-[2-hydroxy-3-(1-isopropylthio-2-methyl-isopropylamino)-propoxy]-6-methyl-indole;

4-(2-hydroxy-3-isopropylaminopropoxy)-6-pivaloyloxymethyl-indole;

4-(2-hydroxy-3-sec.-butylaminopropoxy)-6-pivaloyloxymethyl-indole;

4-[2-hydroxy-3-(1-methylthioisopropylamino)-propoxy]-6-pivaloyloxymethyl-indole;

4-[2-hydroxy-3-(1-methylthio-2-methyl-isopropylamino)-propoxy]-6-pivaloyloxymethyl-indole;

4-[2-hydroxy-3-(1-ethylthio-2-methylisopropylamino)-propoxy]-6-pivaloyloxymethyl-indole;

4-(2-hydroxy-3-isopropylaminopropoxy)-6-methoxymethyl-indole.

The following examples are given for the purpose of illustrating the present invention.

EXAMPLE 1 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-indole

Variant I

A mixture of 5.7 g. 4-(2,3-epoxypropoxy)-indole and 7.1 g. 1-methylthio-2-methylpropyl-2-amine was stirred for 48 hours at ambient temperature. The viscous reaction mixture was dissolved in about 50 ml. diethyl ether and subsequently mixed with ligroin. After filtering with suction and drying the crystals thereby obtained, there were obtained 8.5 g. (92% of theory) chromatographically pure 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-indole; m.p. 119°-120° C.

Variant II

A mixture of 1.9 g. 4-(2,3-epoxypropoxy)-indole and 5 ml. 2,2-dimethyl-aziridine was stirred overnight at ambient temperature and subsequently for a further 4 hours at 40°-50° C. Excess 2,2-dimethyl-aziridine was removed in a vacuum. The residue was taken up in 15 ml. isopropanol. This solution was added slowly, with cooling to 0°-5° C., to a solution, saturated at 0° C., of methyl mercaptan in about 15 ml. isopropanol. After standing for about 20 hours at ambient temperature, excess methyl mercaptan was removed by blowing nitrogen through the reaction mixture. The isopropanol solution was mixed with 1.3 g. benzoic acid and subsequently diluted with 100 ml. diethyl ether. After filtering off with suction and drying the precipitate obtained, there were obtained 2.9 g. of a product with a melting point of 155°-157° C. By the partial evaporation of the mother liquors, there was obtained a second crystallizate (0.8 g.; m.p. 155°-156° C.). The total yield was 3.7 g. (86% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-indole.

Preparation of the benzoate

3.1 g. (0.01 mole) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-indole were dissolved in 50 ml. ethyl acetate and mixed with an equivalent amount of benzoic acid, dissolved in a little ethyl acetate. The precipitate which slowly separates out was, after some time, filtered off with suction and dried. There were obtained 4.0 g. (93% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino-propoxy]-indole benzoate; m.p. 155° C.

EXAMPLE 2 Preparation of 4-[2-hydroxy-3-(1-ethylthio-2-methylisopropylamino)-propoxy]-indole

A mixture of 1.9 g. 4-(2,3-epoxypropoxy)-indole and 3.5 ml. 2,2-dimethyl-aziridine was left to stand for 3 days at ambient temperature. Excess 2,2-dimethyl-aziridine was removed in a vacuum. The residue was taken up in 10 ml. ethyl mercaptan and the solution left to stand for 2 days at ambient temperature. Subsequently, the reaction mixture was evaporated in a vacuum and the residue dissolved in diethyl ether and a a little ethyl acetate. After the addition of 1.2 g. benzoic acid, dissolved in 20 ml diethyl ether, a precipitate was formed. This was filtered off with suction and recrystallized from isopropanol. There were obtained 2.4 g. (54% of theory) 4-[2-hydroxy-3-(1-ethylthio-2-methylisopropylamino)-propoxy]-indole in the form of its benzoate; m.p. 161° C.

EXAMPLE 3 Preparation of 4-[2-hydroxy-3-(1-isopropylthio-2-methylisopropylamino)-propoxy]-indole

A mixture of 1.7 g. 4-(2,3-epoxypropoxy)-indole and 3.5 ml. 2,2-dimethyl-aziridine was left to stand for 3 days at ambient temperature. Excess 2,2-dimethyl-aziridine was removed in a vacuum. The residue was taken up in 20 ml. isopropyl mercaptan and the solution heated to the boil for 20 hours. Subsequently, the reaction mixture was evaporated in a vacuum and worked up in a manner analogous to that described in Example 2. There was obtained 1.5 g. (34% of theory) 4-[2-hydroxy-3-(1-isopropylthio-2-methyl-isopropylamino)-propoxy]-indole in the form of its benzoate; m.p. 132°-133° C.

EXAMPLE 4 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-methyl-indole

A mixture of 5.1 g. 4-(2,3-epoxypropoxy)-2-methyl-indole and 5 ml. 2,2-dimethyl-aziridine was left to stand at ambient temperature for 3 days. Excess 2,2-dimethyl-aziridine was distilled off in a vacuum. The residue was dissolved in 20 ml. isopropanol which had been saturated at 0°-5° C. with methyl mercaptan. The reaction mixture was left to stand for 2 days at ambient temperature and subsequently evaporated. The residue was dissolved in 30 ml. ethyl acetate and the solution mixed with 3.0 g. benzoic acid in 10 ml. diethyl ether. The precipitate obtained was filtered off with suction and recrystalized from about 30 ml. isopropanol. After filtering off with suction and drying, there were obtained 2.0 g. (18% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-methyl-indole in the form of its benzoate; m.p. 151°-152° C.

EXAMPLE 5 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-hydroxymethyl-indole

A mixture of 8.2 g. 4-(2,3-epoxypropoxy)-2-hydroxymethyl-indole and 5.35 g. 1-methylthio-2-methylpropyl-2-amine was left to stand for 24 hours at ambient temperature and subsequently taken up in a mixture of diethyl ether and ethyl acetate. The organic phase was shaken out with dilute acetic acid and discarded. The aqueous acetic acid phase was rendered alkaline and extracted with diethyl ether/ethyl acetate. The solution was washed with water, dried and evaporated. The residue was dissolved in 25 ml. ethyl acetate and the solution mixed with 4.1 g. benzoic acid in 25 ml. ethyl acetate. The first crystals consist almost exclusively of the benzoate of 1-methylthio-2-methylpropyl-2-amine and were discarded. After partial evaporation of the mother liquor and the addition of some diethyl ether, there were obtained 5.2 g. of crude product. This was recrystallized from 100 ml. ethyl acetate. After filtering with suction and drying, there were obtained 3.5 g. (22% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy] -2-hydroxymethyl-indole in the form of its benzoate; m.p. 124°-126° C.

EXAMPLE 6 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-pivaloyloxymethyl-indole

5.3 g. 4-(2,3-epoxypropoxy)-2-pivaloyloxymethyl-indole and 2.5 g. 1-methylthio-2-methylpropyl-2-amine were heated in 5 ml. isopropanol for 36 hours at 50° C. Thereafter, the reaction mixture was evaporated in a vacuum and the residue partitioned between diethyl ether and dilute acetic acid. The acetic acid phase was rendered alkaline and extracted with diethyl ether. The ethereal solution was dried, evaporated somewhat and mixed with benzoic acid. The solution was evaporated in a vacuum and the residue was recrystallized from a little isopropanol. After filtering off with suction and drying, there was obtained 1.5 g. (about 16% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methyl-isopropylamino)propoxy]-2-pivaloyloxymethyl-indole in the form of its benzoate; m.p. 119°-121° C.

EXAMPLE 7 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-ethoxycarbonyl-indole

5.2 g. 4-(2,3-epoxypropoxy)-2-ethoxycarbonyl-indole and 2.6 g. 1-methylthio-2-methylpropyl-2-amine were stirred, with gentle warming, until a homogeneous mixture was formed. After standing overnight at ambient temperature, the reaction mixture was partitioned between diethyl ether/ethyl acetate and dilute acetic acid. The acidic phase was rendered alkaline with potassium carbonate and extracted with ethyl acetate/diethyl ether. The extract was dried, evaporated and the residue subsequently mixed twice with toluene and evaporated each time. The residue was dissolved in about 50 ml. ethyl acetate/diethyl ether and mixed with 1.7 g. benzoic acid. The precipitate obtained was filtered off with suction and dried. There were obtained 4.1 g. (about 40% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamine)-propoxy]-2-ethoxycarbonyl-indole in the form of its benzoate, which sinters at about 85° C.

EXAMPLE 8 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-carbamoyl-indole

9.5 g. 4-(2,3-epoxypropoxy)-2-carbamoyl-indole and 4.4 g. 1-methylthio-2-methylpropyl-2-amine were stirred together, with gentle warming, until a homogeneous mixture was formed. The reaction mixture was left to stand overnight at ambient temperature and then triturated with diethyl ether. The solid residue was filtered off with suction and taken up in 100 ml. isopropanol. To this was added a solution of 3.5 g. maleic acid in 50 ml. isopropanol. The precipitate which slowly separates out was filtered off with suction and dried. There were obtained 3.8 g. (about 23% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-carbamoyl-indole in the form of its maleate; m.p. 119°-121° C.

EXAMPLE 9 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-dimethylaminocarbonyl-indole

9.2 g. 4-(2,3-epoxypropoxy)-2-dimethylaminocarbonyl-indole and 5 ml. 1-methylthio-2-methylpropyl-2-amine were stirred together, with gentle warming, until a homogeneous mixture was formed. After standing for 2 days at ambient temperature, the reaction mixture was triturated three times with diethyl ether. The etheral extract was discarded and the residue was dissolved in ethyl acetate and treated with active charcoal. After the addition of 2.1 g. benzoic acid, dissolved in some ethyl acetate, a precipitate was obtained. This was filtered off with suction and recrystallized twice from some methanol. There were obtained 2.7 g. (18% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-dimethylaminocarbonyl-indole in the form of its benzoate; m.p. 114°-116° C.

EXAMPLE 10 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-carboxy-indole

2.7 g. 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-ethoxycarbonyl-indole (see Example 7) and 0.4 g. potassium hydroxide were dissolved in a mixture of 25 ml. ethanol and 5 ml. water. The solution was maintained at ambient temperature for 24 hours and then at 50° C. for 3 hours. Subsequently, the pH was adjusted to about 3.5 with 2 N hydrochloric acid. The oil which thereby separates out crystallized upon triturating with ethyl acetate and n-butanol. After filtering off the crystals with suction and drying them, there was obtained 1.6 g. (65% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-carboxy-indole hydrate; m.p. 163° C.

EXAMPLE 11 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-2-methoxymethyl-indole

1.4 g. 4-(2,3-epoxypropoxy)-2-methoxymethyl-indole and 0.72 g. 1-methylthio-2-methylpropyl-2-amine were stirred, with gentle warming, to give a homogeneous mixture. After standing for 2 days at ambient temperature, the reaction mixture was dissolved in diethyl ether and the ethereal phase was extracted with 1 N tartaric acid. The organic phase was discarded and the aqueous phase was rendered weakly alkaline with an aqueous solution of sodium bicarbonate and extracted with ether. After drying and evaporating the ethereal solution, the residue was dissolved in a little diethyl ether/ethyl acetate (1:1 v/v) and the solution mixed with 0.6 g. benzoic acid in 5 ml. diethyl ether. The supernatant was decanted off from the initially oily precipitate obtained. The oil crystallizes upon triturating with ethyl acetate (0.5 g.). A further 0.8 g. of crude product was obtained from the decantate after seeding. After recrystallization of the combined crude product from 10 ml. isopropanol, there was obtained 1.0 g. (35% of theory) 4-[b 2-hydroxy-3-(1-methylthio-2-isopropylamino)-propoxy]-2-methoxymethyl-indole in the form of its benzoate; m.p. 104°-107° C.

EXAMPLE 12 Preparation of 4-(2-hydroxy-3-tert.-butylaminopropoxy)-2-pivaloyloxymethyl-indole

3.1 g. 4-(2,3-epoxypropoxy)-2-pivaloyloxymethyl-indole were dissolved in 25 ml. tert.-butylamine. The mixture was left to stand for 2 days at ambient temperature and then evaporated in a vacuum. The residue was partitioned between dilute acetic acid and diethyl ether. The ethereal phase was discarded, the acetic acid solution was rendered weakly alkaline and then extracted several times with diethyl ether. The ethereal solution was dried and evaporated. The crystalline residue (1.9 g.) was again taken up in diethyl ether and the solution mixed with 0.63 g. benzoic acid. The precipitate which slowly separated out was, after some time, filtered off with suction and dried. There was obtained 2.0 g. (40% of theory) chromatographically pure 4-(2-hydroxy-3-tert. butylaminopropoxy)-2-pivaloyloxymethyl-indole in the form of its benzoate; m.p. 149°-150° C.

The 4-(2,3-epoxypropoxy)-2-pivaloyloxymethyl-indole used as starting material can be prepared as follows:

11.5 g. 4-(2,3-epoxypropoxy)-2-hydroxymethyl-indole (see U.S. Pat. No. 3,705,907) were dissolved in 100 ml. pyridine. To this solution were added dropwise, while cooling to 0°-5° C., 6.5 g. (6.7 ml.) pivaloyl chloride. After an hour, the reaction mixture was poured on to ice and extracted with diethyl ether. The ethereal solution was successively washed with dilute sulfuric acid, aqueous sodium bicarbonate solution and water. After drying and treating with active charcoal, the solution was filtered and evaporated. The residue (13 g.; 82% of theory) crystallized upon triturating with diethyl ether/ligroin to give 4-(2,3-epoxypropoxy)-2-pivaloyloxymethyl-indole; m.p. 129°-131° C.

EXAMPLE 13 Preparation of 4-(2-hydroxy-3-isopropylaminopropoxy)-2-pivaloyloxymethyl-indole

According to the process described in Example 12, from 2.6 g. 4-(2,3-epoxypropoxy)-2-pivaloyloxymethyl-indole and 10 ml. isopropylamine, there was obtained 1.1 g. (27% of theory) 4-(2-hydroxy-3-isopropylaminopropoxy)-2-pivaloyloxymethyl-indole in the form of its benzoate; m.p. 133°-135° C.

EXAMPLE 14 Preparation of 4-(2-hydroxy-3-cyclopropylaminopropoxy)-2-pivaloyloxymethyl-indole

According to the process described in Example 12, from 2.0 g. 4-(2,3-epoxypropoxy)-2-pivaloyloxymethyl-indole and 4 ml. cyclopropylamine, there were obtained 2.7 g. (85% of theory) 4-(2-hydroxy-3-cyclopropylaminopropoxy)-2-pivaloyloxymethyl-indole in the form of its benzoate; m.p. 146°-147° C.

EXAMPLE 15 Preparation of 4-(2-hydroxy-3-tert.-butylaminopropoxy)-6-hydroxymethyl-indole

5 g. 4-(2,3-epoxypropoxy)-6-hydroxymethyl-indole were dissolved in 25 ml. tert.-butylamine. The mixture was left to stand for 2 days at ambient temperature, subsequently boiled gently for about an hour and then evaporated in a vacuum. The residue was partitioned between dilute acetic acid and diethyl ether. The ethereal phase was discarded and the acetic acid solution was rendered alkaline and then shaken out with ether. After drying and evaporating the ethereal phase, the base thereby obtained was recrystallized from a little ethyl acetate/diethyl ether (3.3 g. of base; m.p. 129°-131° C.). 3.0 g. of this base were dissolved in a mixture of about 100 ml. ethyl acetate and 20 ml. isopropanol. Upon the addition of 1.2 g. benzoic acid, the benzoate slowly precipitates out. After filtering off with suction and drying, there were obtained 3.4 g. (41% of theory) 4-(2-hydroxy-3-tert.-butylaminopropoxy)-6-hydroxymethyl-indole in the form of its benzoate; m.p. 190°-191° C.

The 4-(2,3-epoxypropoxy)-6-hydroxymethyl-indole used as starting material is prepared as follows:

4-Acetoxy-6-methoxycarbonyl-indole, obtained by the modification of a process described by N. R. El-Rayyes (J. prakt. Chem., 315, 295/1973), was saponified with sodium methylate, with the exclusion of oxygen, to give 4-hydroxy-6-methoxycarbonyl-indole. 22.2 g. of the 4-hydroxy-6-methoxycarbonyl-indole thus obtained, 16.5 g. dry potassium carbonate and 15.9 ml. benzyl chloride were heated for 3 hours to 80°-90° C., while stirring, in 200 ml. anhydrous dimethyl formamide. About 100-150 ml. dimethyl formamide were evaporated off in a vacuum and the residue is mixed with water and diethyl ether. The ethereal phase was separated off and the aqueous phase extracted several times with diethyl ether. The combined ethereal extracts were dried, clarified with active charcoal and evaporated. The crystallized residue was, with the addition of active charcoal, recrystallized from ethanol. There were obtained 18.0 g. (53.5% of theory) of almost colorless crystals; m.p. 160°-162° C.

A solution of 24.5 g. of the 4-benzyloxy-6-methoxycarbonylindole thus obtained in 150 ml. anhydrous tertrahydrofuran was added dropwise, while stirring and cooling to 15°-20° C., into a suspension of 5.3 g. lithium aluminum hydride in 150 ml. anhydrous tetrahydrofuran. After 4 hours, excess reducing agent was decomposed by the addition of 25 ml. of a saturated aqueous solution of sodium chloride. The precipitate obtained was filtered off with suction and washed with diethyl ether. The filtrate was dried, treated with active charcoal and evaporated. The brownish oil which remains behind crystallized upon triturating with diethyl ether/ligroin. After filtering off with suction and drying, there were obtained 18.6 g. (83% of theory) of lightly colored crystals; m.p. 118°-120° C.

18.5 g. of the 4-benzyloxy-6-hydroxymethylindole thus obtained were hydrogenated in 200 ml. methanol, with the addition of 3.0 g. of a palladium-charcoal catalyst (10:90), at atmospheric pressure and ambient temperature. After 2 hours, no starting material can be detected in a thin layer chromatogram. The catalyst was filtered off with suction and the filtrate was evaporated in a vacuum. The solid residue was intensively triturated with diethyl ether and filtered off with suction. There were obtained 10.0 g. (84% of theory 4-hydroxy-6-hydroxymethyl-indole; m.p. 168°-169° C.

3.3 g. of the 4-hydroxy-6-hydroxymethyl-indole thus prepared were dissolved in 30 ml. epichlorohydrin. To this solution were added dropwise, while stirring at ambient temperature, over the course of 1 hour, 20 ml. 2 N sodium methylate solution. After about 5 hours, the starting material had reacted. The solution was evaporated in a vacuum and the residue was mixed with water, as well as with a mixture of diethyl ether and ethyl acetate. The organic phase was shaken out several times with water, subsequently dried, treated with active charcoal and evaporated. The crude 4-(2,3-epoxypropoxy)-6-hydroxymethyl-indole thus obtained (about 5 g. of a brownish oil) contains, as by-product, some 4-(2-hydroxy-3-chloropropoxy)-6-hydroxymethyl-indole but was further used without further purification.

EXAMPLE 16 Preparation of 4-(2-hydroxy-3-isopropylaminopropoxy)-6-hydroxymethyl-indole

In the same manner as described in Example 15, from 5.1 g. 4-(2,3-epoxypropoxy)-6-hydroxymethyl-indole and 25 ml. isopropylamine, there were obtained 3.3 g. (41% of theory) 4-(2-hydroxy-3-isopropylaminopropoxy)-6-hydroxymethyl-indole in the form of its benzoate; m.p. 171°-172° C.

EXAMPLE 17 Preparation of 4-(2-hydroxy-3-tert.-butylaminopropoxy)-6-methyl-indole

2.3 g. 4-(2,3-epoxypropoxy)-6-methyl-indole were dissolved in 25 ml. tert.-butylamine. The reaction mixture was left to stand for 3 days at ambient temperature and subsequently evaporated in a vacuum. The residue was subjected to an acidic separation in the manner described in Example 15. The residue (2.2 g.) thereby obtained was dissolved in a little ethyl acetate. Upon adding 1.0 g. benzoic acid, a crystalline precipitate gradually separates out. After filtering off with suction and drying, there was otained 1.5 g. (33% of theory) 4-(2-hydroxy-3-tert.-butylaminopropoxy)-6-methyl-indole in the form of its benzoate; m.p. 198°-200° C.

The 4-(2,3-epoxypropoxy)-6-methyl-indole used as starting material was obtained in the following manner:

A solution of 10.6 g. 4-benzyloxy-6-hydroxymethylindole (cf. the preparation of the starting material in Example 15) in 50 ml. pyridine was carefully mixed with 50 ml. acetic anhydride. The reaction mixture was left to stand overnight at ambient temperature and subsequently evaporated in a vacuum at 40° C. The residue was taken up in diethyl ether. The ethereal phase was successively washed with water, 1 N sulfuric acid and again with water. The dried solution was treated with active charcoal and evaporated. There were obtained 9.9 g. (about 80% of theory) 4-benzyloxy-6-acetoxymethyl-indole which, as crude product, was further worked up; m.p. 98°-100° C.

9.8 g. of the 4-benzyloxy-6-acetoxymethyl-indole thus obtained were hydrogenated in 200 ml. methanol with the addition of 2 g. of a palladium-charcoal catalyst (10:90). After about 3 hours, no more starting material was present. The catalyst was filtered off with suction and the filtrate was evaporated in a vacuum. The 4-hydroxy-6-methyl-indole obtained in almost 100% yield as a pale yellowish oil was, without purification, further reacted.

6.4 l g. of crude 4-hydroxy-6-methyl-indole were reacted and further worked up with epichlorohydrin in the manner described in Example 15. The mixture of 4-(2,3-epoxypropoxy)-6-methyl-indole and 4-(2-hydroxy-3-chloropropoxy)-6-methyl-indole thereby obtained was chromatographed on a column of silica gel (elution with methylene chloride/methanol 99:1-95:5). In this way, there were obtained 2.8 g. (41.5% of theory, referred to the 4-benzyloxy-6-acetoxymethyl-indole) of chromatographically pure 4-(2,3-epoxypropoxy)-6-methyl indole as an almost colorless oil.

EXAMPLE 18 Preparation of 4-(2-hydroxy-3-isopropylaminopropoxy)-6-methyl-indole

According to the process described in Example 17, from 4.0 g. 4-(2,3-epoxypropoxy)-6-methyl-indole and 25 ml. isopropylamine, there were obtained 3.0 g. (41% of theory) 4-(2-hydroxy-3-isopropylaminopropoxy)-6-methyl-indole in the form of its benzoate; m.p. 182°-184° C.

EXAMPLE 19 Preparation of 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-6-methyl-indole

A mixture of 2.8 g. 4-(2,3-epoxypropoxy)-6-methyl-indole and 3.0 ml. 2,2-dimethyl-aziridine was left to stand for 2 days at ambient temperature. Excess 2,2-dimethyl-aziridine was removed in a vacuum. The residue was dissolved in a little isopropanol and subsequently mixed with 50 ml. of a solution of methyl mercaptan, saturated at 0° C., in isopropanol. After 2 days, the reaction mixture was evaporated in a vacuum. The residue was dissolved in 35 ml. ethyl acetate. After the addition of a solution of 1.7 g. benzoic acid in 10 ml. diethyl ether, a precipitate separates out. There were obtained 3.0 g. (50% of theory) 4-[2-hydroxy-3-(1-methylthio-2-methylisopropylamino)-propoxy]-6-methyl-indole in the form of its benzoate; m.p. 174°-175° C.

EXAMPLE 20 Preparation of 4-(2-hydroxy-3-tert.-butylaminopropoxy)-6-pivaloyloxymethyl-indole

12.7 g. 4-(2,3-epoxypropoxy)-6-pivaloyloxymethyl-indole were kept for 2 days at ambient temperature in 50 ml. tert.-butylamine. Excess tert.-butylamine was then distilled off in a vacuum. The residue was dissolved in 1 N acetic acid and the solution was extracted with diethyl ether. The aqueous phase was rendered alkaline with a dilute aqueous solution of potassium carbonate and shaken out with a mixture of diethyl ether/ethyl acetate. The organic phase was dried, treated with active charcoal and evaporated. The residue was dissolved in 50 ml. ethyl acetate and the solution mixed with 2.6 g. benzoic acid, dissolved in 30 ml. diethyl ether. The precipitate which was obtained was filtered off with suction and recrystallized from a 1:1 mixture of methanol and ethanol. There were obtained 5.3 g. (35% of theory) 4-(2-hydroxy-3-tert.-butylaminopropoxy)-6-pivaloyloxymethyl-indole in the form of its benzoate; m.p. 194°-195° C.

The 4-(2,3-epoxypropoxy)-6-pivaloyloxymethyl-indole used as starting material was prepared as follows:

8.7 g. 4-(2,3-epoxypropoxy)-6-hydroxymethyl-indole (cf. the preparation of the starting material in Example 15) were dissolved in 50 ml. anhydrous pyridine. To this solution were added dropwise, while stirring and cooling to 5°-10° C., 5 ml. pivalic acid chloride, 1.5-2 hours after the ending of the addition, the reaction mixture was poured into ice water. The aqeuous phase was extracted 3 or 4 times with diethyl ether. The ethereal extract was successively washed with 1 N sulfuric acid, a saturated aqueous solution of sodium bicarbonate and water, then dried, treated with active charcoal and fullers' earth and subsequently evaporated. The crude 4-(2,3-epoxypropoxy)-6-pivaloyloxymethyl-indole thus obtained (12.5 g.; about 100% of theory) was further reacted without further purification.

EXAMPLE 21 4-(2-hydroxy-3-tert.-butylamino-propoxy)-2-ethoxycarbonyl-6-methylindole

1.7 g 4-(2,3-epoxypropoxy)-2-ethoxycarbonyl-6-methyl-indole are dissolved in 25 ml tert.-butylamine. The solution is stored at room temperature for three days and then evaporated in vacuum. The residue is triturated with ether and aspirated. The crude product is dissolved in hot acetic ester and the solution is mixed with 0.3 ml glacial acetic acid. The precipitate resulting after cooling of the solution is aspirated and dried. There is obtained 1.8 g (˜71% of theory) of 4-(2-hydroxy-3-tert.-butylamino-propoxy)-2-ethoxycarbonyl-6-methylindole as acetate; m.p. 181°-183° C.

The 4-(2,3-epoxypropoxy)-2-ethoxycarbonyl-6-methylindole used as starting material is prepared as follows:

To a composition of 39.5 g, 2,5-dimethyl-3-nitrophenol (obtained according to St. v. Kostanecki, B. 19, 2318 [1886]), 33.0 g dried and pulverized potassium carbonate, as well as 250 ml abs. DMF there is added, dropwise, 30 ml benzyl chloride while stirring, at room temperature. The mixture is stirred for 2 to 3 additional days and then aspirated. The filtrate is evaporated in vacuum and the oily residue is stirred into about 1 liter ice water. The precipitate deposit is aspirated and recrystallized from isopropanol. There is obtained 45.7 g (˜75% of theory) of 2,5-dimethyl-3-nitro-O-benzylphenol; melting point: 69°-71° C.

25.7 g of the thus obtained 2,5-dimethyl-3-nitro-O-benzylphenol are added in portions during stirring to a mixture of 17 g freshly prepared potassium-tert.-butylate and 120 ml oxalic acid diethyl ester. After completion of the addition, the mixture is heated to 60° C. for two hours. After cooling, the composition is mixed with 200 ml ether and carefully acidified with diluted acetic acid. The ether phase is washed with neutral water, dried and evaporated. The still present oxalic ester is distilled off in the water jet vacuum at increased bath temperature. The residue is dissolved in ether and the solution is carefully mixed with ligroin. After aspirating and drying, there is obtained 30.6 g (˜85° of theory) 2-benzyloxy-4-methyl-6-nitro-phenyl pyruvic acid ethyl ester; m.p. 80°-82° C.

The solution of 30.6 g of the thus prepared 2-benzyloxy-4-methyl-6-nitrophenyl pyruvic acid ethyl ester in a composition of 250 ml glacial acetic acid and 15 ml water is brought to boiling. The heating is removed and the solution is mixed with 33.6 g zinc dust in such a manner that the boiling temperature is maintained. 5.6 g zinc dust is additionally added and heated to boiling for 30 minutes. The mixture is aspirated from the excessive zinc dust while still hot. The filter cake is washed well with glacial acetic acid and ethanol. The precipitate resulting during the cooling of the filtrate is aspirated and dried. There is obtained 15.7 g (˜59% of theory) 4-benzyloxy-2-ethoxycarbonyl-6-methylindole; m.p. 167°-168° C.

11.0 g of the thus obtained 4-benzyloxy-2-ethoxycarbonyl-6-methyl indole are suspended in 150 ml methanol and, after addition of a suspension of 1.0 g, 10% Pd/C in 20 ml ethanol hydrogenated at normal pressure in a duck-shaped shaking vessel. The catalyst is aspirated and the filtrate is evaporated. There is obtained pure 4-hydroxy-2-ethoxycarbonyl-6-methylindole in virtually quantitative yield.

7.8 g of the thus obtained 4-hydroxy-2-ethoxycarbonyl-6-methylindole are dissolved in 100 ml epichlorohydrine and the solution is heated subsequent to the addition of 5 to 6 drops of piperidine, to boiling. After about 3 to 4 hours, the solution is evaporated in vacuum and the residue is recrystallized from isopropanol. There is obtained 6.4 g (˜64% of theory) 4-(2,3-epoxypropoxy)-2-ethoxycarbonyl-6-methyl indole; m.p. 173°-175° C.

EXAMPLE 22 4-(2-hydroxy-3-isopropylamino-propoxy)-2-ethoxycarbonyl-6-methyl indole

2.0 g 4-(2,3-epoxypropoxy)-2-ethoxycarbonyl-6-methyl indole are dissolved in 25 ml isopropylamine. The solution is kept for two days at room temperature and then heated to boiling for 8 to 10 hours. Excessive isopropyl amine is removed in vacuum and the residue triturated with ether. The crude product is dissolved in small amounts of isopropanol during heating. After the addition of 0.42 ml glacial acetic acid, the solution is allowed to cool. The precipitated deposit is aspirated and recrystallized from small amounts of isopropanol. There is obtained 1.6 g (55% of theory) 4-(2-hydroxy-3-isopropylamino-propoxy)-2-ethoxycarbonyl-6-methylindole as acetate; m.p. 163°-165° C.

EXAMPLE 23 4-(2-hydroxy-3-tert.-butylamino-propoxy)-2-carbamoyl-6-methyl indole

1.5 g of 4-(2,3-epoxypropoxy)-2-carbamoyl-6-methyl indole in 25 ml tert.-butylamine is heated to boiling for 24 hours. The solution is then evaporated and the residue dissolved in chloroform. The chloroform solution is washed with water, dried and evaporated. The residue is suspended in hot acetic ester and mixed with 0.8 g benzoic acid. A clear solution will result here, from which a precipitate deposits. This is aspirated and recrystallized from 100 ml acetic ester. There is obtained 1.5 g (55% of theory) 4-(2-hydroxy-3-tert.-butylaminopropoxy)-2-carbamoyl-6-methyl indole as benzoate; m.p. 213°-214° C.

The 4-(2,3-epoxypropoxy)-2-carbamoyl-6-methyl indole used as starting material is obtained in the following manner:

20.0 g 4-benzyloxy-2-ethoxycarbonyl-6-methyl indole (see preparation of the primary products in connection with Example 1) are heated together with 200 ml each of methanol and liquid ammonia in the autoclave for 16 hours, to 100° C. The solution is evaporated and the residue is chromatographed on silica gel (fluxing agent: chloroform/methanol 98:2). There is obtained 8.5 g (˜46% of theory) 4-benzyloxy-2-carbamoyl-6-methyl indole; m.p. 185°-187° C.

8.5 g of the thus obtained 4-benzyloxy-2-carbamoyl-6-methyl indole are hydrogenated in a composition of 100 ml methanol and 50 ml ethylene glycol-dimethyl ether during addition of 1.0 g 10% Pd/C up to the absorption of the theoretical amount of hydrogen. The catalyst is aspirated and the filtrate is evaporated in vacuum. There is obtained 5.4 (˜93% of theory) 4-hydroxy-2-carbamoyl-6-methyl indole as a light yellow syrup.

The material obtained above (5.4 g) is dissolved in 50 ml epichlorohydrine. There is added, dropwise, into this solution 28.4 ml 2 N sodium methylate solution while stirring at room temperature for about 12 hours. The solution is stirred without addition of the sodium methylate for approximately 4 to 6 hours and then evaporated. The residue is absorbed in chloroform and the chloroform solution is washed neutral, treated with active carbon, as well as adsorbing clay, dried and evaporated. The residue is chromatographed on silica gel (fluxing agent: chloroform/methanol 98:2). There is obtained 1.5 g (˜21% of theory) 4-(2,3-epoxy-propoxy)-2-carbamoyl-6-methyl indole as a colorless syrup.

EXAMPLE 24 4-(2-hydroxy-3-isopropylamino-propoxy)-2-dimethylaminocarbonyl-6-methyl indole

The suspension of 2.5 g 4-(2,3-epoxypropoxy)-2-dimethyl-aminocarbonyl-6-methyl indole in a composition of 25 ml isopropyl amine and 10 ml DMF is heated to boiling for 24 hours. The solution is evaporated in vacuum and the residue is diturated with ether and aspirated. The solid material is heat-dissolved in 35 ml isopropanol and the solution is mixed with 1.0 g benzoic acid. The precipitated deposit is aspirated and recrystallized from isopropanol. There is obtained 2.3 g (55% of theory) 4-(2-hydroxy-3-isopropylaminopropoxy)-2-dimethylaminocarbonyl-6-methyl indole as benzoate; m.p. 169°-171° C.

The 4-(2,3-epoxypropoxy)-2-dimethylaminocarbonyl-6-methyl indole used as starting material is obtained as follows:

31.0 4-benzyloxy-2-ethoxycarbonyl-6-methyl indole (see preparation of the primary products in connection with Example 1) are heated to boiling in a mixture of 100 ml ethanol and 100 ml water during addition of 7.0 potassium hydroxide, for 2 to 3 hours. The ethanol is then evaporated in vacuum and the remaining, water alkaline solution is acidified with conc. hydrochloric acid. The resulting precipitate is aspirated, thoroughly washed with water and dried. There is obtained 27.6 g (˜95% of theory) 4-benzyloxy-2-carboxy-6-methyl indole; m.p. 178°-180° C.

5.4 g of the above obtained acid are added to a solution of N,N'-thionyl diimidazole prepared from 10.9 g imidazole and 3.0 ml thionyl chloride in 50 ml abs. THF and previously aspirated from precipitated imidazole hydrochloride. The solution is stirred for 3 hours at room temperature and then 0° C. dry dimethylamine (˜0.5-1.0 hours) is introduced. The solution is then evaporated in vacuum and the residue is absorbed in chloroform. The chloroform phase is repeatedly washed with water, dried and evaporated. After recrystallization from butanol during addition of active carbon, there is obtained 2.4 g (˜40% of theory) 4-benzyloxy-2-dimethylaminocarbonyl-6-methylindole; m.p. 205°-207° C.

10.7 g of the thus prepared 4-benzyloxy-2-dimethylaminocarbonyl-6-methyl indole are suspended in a mixture of 100 ml methanol and 100 ml ethylene glycol dimethyl ether and hydrogenated after the addition of 1.0 g 10% Pd/C. The catalyst is aspirated and the filtrate is evaporated. There is obtained 7.6 g (˜98% of theory) 4-hydroxy-2-dimethylaminocarbonyl-6-methylindole as a brownish solid body, which is further processed without purification.

The above-obtained raw product (7.6 g) is absorbed in 75 ml epichlorohydrine and the solution is mixed, drop by drop, during stirring at room temperature with 21.0 ml 2 N sodium methylate solution for 7 to 8 hours. The solution is allowed to stand at room temperature over night and then it is evaporated. The residue is absorbed in chloroform and the chloroform solution is repeatedly washed with water, dried, treated with charcoal, as well as absorbing clay, and evaporated. The solid residue is triturated with little ether and sucked off. One obtains 4.9 g (˜51% of theory) 4-(2,3-epoxypropoxy)-2-dimethylaminocarbonyl-6-methylindole (m.p. 197°-204° C.), which is still adulterated with some 4-(2-hydroxy-3-chloropropoxy)-2-dimethylaminocarbonyl-6-methyl indole.

The following tests were carried out to determine the cardiac β-receptor blocking activity of certain test compounds by determining the inhibition of the heart beat frequency increase induced by intravenous administration of isoprenalin.

The test compounds representative of the invention were the following:

    ______________________________________                                         Compound I:                                                                              4-[2-Hydroxy-3-(1-methylmercapto-2-methyl-                                     isopropylamino)propoxy]-indole                                       Compound II:                                                                             4-(2-Hydroxy-3-tert.-butylamino-propoxy)-2-                                    pivaloyloxymethyl-indole                                             Compound III:                                                                            4-(2-Hydroxy-3-isopropylamino-propoxy)-2-                                      pivaloyloxymethyl-indole                                             Compound IV:                                                                             4-(2-Hydroxy-3-tert.-butylamino-propoxy)-6-                                    hydroxymethyl-indole                                                 Compound V:                                                                              4-(2-Hydroxy-3-tert.-butylamino-propoxy)-6-                                    methyl-indole                                                        Compound VI:                                                                             4-(2-Hydroxy-3-isopropylamino-propoxy)-6-                                      methyl-indole                                                        ______________________________________                                    

A comparison compounds there was included:

    ______________________________________                                         Compound A:                                                                             1-Isopropylamino-3-(1-naphthoxy)-2-propanol                                    (Propranolol)                                                         ______________________________________                                    

These compounds were tested in the following manner:

The β-receptor blocking activity of the test compounds was tested on wake rabbits weighing between 2 to 3.5 kg and kept in wooden cages. EKG-electrodes were inserted into the hind quarters of the rabbits s.c. (II. lead) and the heart frequency was measured using an integrator (15 seconds) as a digital value. The test compounds were then infused through a small tube to the ear vein of the rabbits over a period of 15 minutes. 30 Minutes after the infusion isoprenalin (3,4-dihydroxy-α-[(isopropylamino)-methyl]-benzylalcohol) was injected intravenously at 1 μg/kg.

The results are set forth in terms of inhibition of isoprenalin tachycardia, and are set forth in the table below:

                  TABLE                                                            ______________________________________                                         Blocking of Isoprenalin Tachycardia                                            in Wake Rabbits                                                                Test     Dosage     Heartbeat Frequency                                                                           ˜DE.sub.250*                          Substance                                                                               mg/kg i.v.  -x ± S.sub.x-                                                                             mg/kg i.v.                                  ______________________________________                                         Control  without iso-                                                                   prenalin   205 ±  9    --                                          Control  with Isopren-                                                                  alin       338 ± 10    --                                          Compound A                                                                     (Propranolol)                                                                           0.01       342 ±  5    0.400                                                0.1        309 ±  9                                                         0.25       259 ±  7                                                         0.5        248 ±  6                                                         1.0        210 ±  8                                                         4.0        191 ±  6                                                Compound I                                                                              0.05       332 ±  6    --                                          (Example 1)                                                                             0.01       264 ±  6    0.140                                                0.2        236 ± 10    --                                                   0.5        203 ±  9    --                                          Compound II                                                                             0.01       275 ±  3    --                                          (Example 12)                                                                            0.05       228 ± 10    0.020                                                0.1        223 ±  8    --                                                   1.0        196 ± 11    --                                          Compound III                                                                            0.01       305 ± 14    --                                          (Example 13)                                                                            0.025      275 ±  6    --                                                   0.05       247 ± 10    0.090                                                0.1        248 ±  7    --                                                   0.5        217 ±  7    --                                                   1.0        205 ±  5    --                                          Compound IV                                                                             0.05       268 ± 13    --                                          (Example 15)                                                                            0.1        283 ±  8    0.300                                                0.5        238 ±  7    --                                                   1.0        222 ± 19    --                                          Compound V                                                                     (Example 17)                                                                            0.01       278 ±  6    --                                                   0.02       239 ±  7    --                                                   0.05       217 ± 10    0.016                                                1.0        206 ± 11    --                                                   5.0        247 ± 26    --                                          Compound VI                                                                             0.005      332 ±  6    --                                          (Example 18)                                                                            0.025      281 ± 12    --                                                   0.05       249 ±  5    --                                                   0.1        264 ±  9    0.090                                                0.25       299 ±  7    --                                                   0.5        208 ±  9    --                                                   1.0        216 ±  8                                                ______________________________________                                          *Interpolated dosage which limits the frequency increase to 250 beats/min                                                                               

The above data show dosage that the inventive compounds are already effective at a dosage much smaller than those required of the comparison substances.

The compounds according to the present invention are thus unexpectedly superior in effectiveness to known compounds and thus present a valuable contribution to the art.

The dosage of the novel compounds of the present invention depend on the age, weight, and condition of the patient being treated. Generally speaking, for adultoral administration, the preferred unit dosage of active compound with suitable pharmaceutical diluent or lubricant is 1 mg.-40 mg. four times a day. In general the oral dosage is 20-40 mg., whereas the intravenous dosage is generally 1-5 mg., four times a day.

For preparing therapeutic compositions such as tablets and other compressed formulations, the compounds can include any compatible and edible tableting material used in pharmaceutical practice as for example, corn starch, lactose, stearic acid, magnesium stearate, talc, methyl cellulose and the like.

Similarly the compounds of the present invention can be mixed with suitable adjuvants for the preparation of resorbable hard gelatin or soft capsules utilizing conventional pharmaceutical practices.

Further, the compounds can be employed in the form of their solutions or suspensions suitable for parenteral administrations.

It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention. 

What is claimed is:
 1. Amino propanol of the formula ##STR7## wherein R is lower alkyl or cycloalkyl of from 3 to 6 carbon atomsR₁ is pivaloyloxyalkyl, and R₂ is hydrogen, lower alkyl, hydroxyalkyl, alkoxyalkyl or pivaloyloxyalkyl;wherein the alkyl moieties contain up to 6 carbon atoms each; and the pharmacologically acceptable salts thereof.
 2. Aminopropanol compound as claimed in claim 1 wherein R is alkyl of up to 6 carbon atoms.
 3. Aminopropanol compound as claimed in claim 1 wherein R is cycloalkyl.
 4. Aminopropanol compound as claimed in claim 1 wherein R₁ is pivaloyloxyalkyl and R₂ is hydrogen.
 5. Aminopropanol compound as claimed in claim 1 designated 4-(2-hydroxy-3-tert.-butylamino-propoxy)-2-pivaloyloxymethyl-indole.
 6. Aminopropanol compound as claimed in claim 1 designated 4-(2-hydroxy-3-isopropylamino-propoxy)-2-pivaloyloxymethyl-indole.
 7. Method of combatting or preventing cardiac and circulatory infirmities which method comprises applying to a subject in amounts effective for treatment or prophylaxis of cardiac or circulatory diseases an aminopropanol compound selected from4-(2-hydroxy-3-tert.-butylamino-propoxy)-2-pivaloyloxymethyl-indole, and 4-(2-hydroxy-3-isopropylamino-propoxy)-2-pivaloyloxymethyl-indole.
 8. Method as claimed in claim 7 wherein said compound is4-(2-hydroxy-3-tert.-butylamino-propoxy)-2-pivaloyloxymethyl-indole.
 9. Method as claimed in claim 7 wherein said compound is applied at a dosage of 1 to 40 mg up to four times a day.
 10. Method as claimed in claim 7 wherein said compound is applied orally in dosages of 20 to 40 mg.
 11. Method as claimed in claim 7 wherein said compound is applied intravenously at a dosage of from 1 to 5 mg per dosage. 